1. Field of the Invention
The present invention relates to a riding mower having left and right driving rear wheels independently drivable forward and backward, a pair of left and right steerable front wheels, a driver's seat provided in a space between the rear wheels and the front wheels, and a gate-shaped rollover protection frame having a lower end side fixed to a left and right positions on the rear side of the driver's seat.
2. Description of Related Art
Such a riding mower having left and right driving rear wheels independently drivable forward and backward and a pair of left and right steerable front wheels is generally mounted with a gasoline engine. A fuel tank is provided under an engine hood or under a rear wheel fender between the rear wheel fender and the rear wheel (refer to Related Art 1).    [Related Art 1] Japanese Patent Laid-Open Publication No. 2000-351330 (paragraph [0029]; FIGS. 1 and 2)
Fuel gas, such as LP gas, has recently been attempted to be used as an alternative fuel to gasoline in view of benefits of the fuel gas, such as LP gas, in reduction in CO2 and fuel cost. To use the fuel gas, such as LP gas, however, a large capacity gas cylinder should be mounted for driving. It is difficult in view of space to place such a gas cylinder under an engine hood or under a rear wheel fender. It is thus considered to dispose the gas cylinder on the engine hood or on the rear wheel fender. In either case, providing a large gas cylinder in a relatively high position on a vehicle body possibly destabilizes the vehicle body due to the high gravity center and obscures rearward visibility or side visibility.